The invention relates to preparing recesses or holes in bones of humans or animals. In such recesses or holes implants e.g. in the form of screws may be introduced. Such screws may be used for example to treat fractures of bones.
Conventionally, the recesses were generally drilled with a rotating tool and both the recesses and the screws or pins to be inserted therein usually have a circular cross-section. Due to this circular cross-section, a single recess-screw-combination is not suitable to accommodate rotation forces applied around the axis of the screw. In order to accommodate such rotation forces which may occur for example when fixing two parts of bones together or when fixing an implant to a bone, it has been necessary to provide a plurality of screws or pins inserted into a plurality of recesses prepared in the bone.
The necessity of preparing a plurality of recesses in a bone for example during a surgical intervention requires additional work for a physician. Furthermore, the preparation of a plurality of recesses in a bone may increase the discomfort for a patient and may delay the healing.